In fairness to all, we don't discuss pricing on the Wall. Thanks for your cooperation.
I have a customer with a boiler that continually goes off in low water. Smith boiler with powerflame burner. The near boiler is far from perfect, but has been there a long time and I believe this is a new problem. 2 risers with take off between.
Secondary lwco is installed in the equallizer in rear of boiler, well below the level in the feeder/primary control in the front of the boiler. Wet return T is above the water line. Original secondary (MM probe) appreared faulty, so I replaced with the required manual reset, I fired boiler and it made steam in 10 minutes and made pressure in 16.
Another no heat call. Boiler had plenty of water in glass, but lwco in reset. I reset the lwco and the burner fired. During initial few minutes, before making steam, water level in the glass went up and the boiler went into lwco condition indicating a "false waterline" condition. Once the boiler made steam, this seamed to settle down.
I remember reading about this in Dan's books, but can't remember cure and do not have access to my copies for a few days.